Shock absorbing and pressure reducing insole

ABSTRACT

Shock absorbing and pressure reducing insole for footwear with one or several cavities filled with fluid. In the cavity, additional joints have been provided between the top foil and the bottom foil of the insole in order to damp the movement of the fluid in the insole. The additional joints have varying heights in order to promote presence of fluid near the higher joints.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a shock absorbing and pressurereducing insole as described in the preamble of claim 1. The inventionalso relates to a process of manufacturing as well as to use of aninsole.,

[0002] A larger number of insoles for footwear are known, where theinsole is filled with a fluid, for example gas, liquid or gel.Typically, the insole is manufactured by joining, for example welding orgluing, two foils together along the edge of the insole. Thus, anenclosed cavity is produced which is filled with fluid before or duringthe joining.

[0003] Apart from the joint along the edge, the insole can be providedwith additional joints in a particular pattern in order to obtain amassaging or pressure reducing-effect.

[0004] Such soles are described in international patent application WO94/23603 and in U.S. Pat. Nos. 4,123,855, 5,778,561, 5,979,086,4,567,677 and 5,067,255. These massaging insoles are characterised inthat one or several liquid cavities are provided extending from the rearof the insole to the front of the insole. The massaging effect arises asa result of the movement of the liquid in-between the heel area and thearea under the forefoot as the load on the foot is changed. These solesmay be provided with joint patterns designed to obstruct the movement ofthe liquid, which prolongs the response time of the sole, thus, creatinga shock absorbing effect. Furthermore, joints on the insole under themiddle of the foot prevent the liquid from gathering at this particularplace. The disadvantage of these soles is that a continued load on theheel or forefoot will cause the liquid to flow to the opposite end ofthe insole, thus, removing the supporting liquid from under the heel andforefoot, respectively.

[0005] In order to maintain the liquid support under the heel andforefoot, respectively, an insole has been developed and described inU.S. Pat. No. 4,115,934, in which an insole has been provided withsmaller cavities under the heel and under the forefoot.

[0006] However, such a construction has great disadvantages. Through aload placed such on a cavity, which for example is established centrallyunder the heel, the liquid will be displaced from the centre to theperiphery of the cavity. This principle is not appropriate for thininsoles because all the liquid is displaced from the middle of thecavity to the periphery due to loading. This effect is increasinglysignificant by long term use, as a repeated load causes so-called creepof the foil material, which results in an easier displacement of theliquid to the periphery of the cavity. Consequently, load by the heelwill cause the absence of liquid under the heel. This effect can becounteracted by using very thick insoles, where the cavities contain alarge amount of fluid, or where part of the liquid is substituted by asponge material as in U.S. Pat. No. 5,313,717. However, thick insolescan be difficult to fit into existing footwear. Furthermore, a high,liquid filled insole diminishes the support of the foot by the footwear.

[0007] Another disadvantage is that load by the heel causes the liquidto flow from the middle of the heel area to the periphery of the heelcavity within a very short time, whereby the shock absorption is limitedconsiderably. Also, the well known long-term problem of creep of thematerial has the effect that both shock absorption and pressurereduction decrease substantially with time. In addition to this, thedisplacement of the liquid to the periphery of the cavity causesproblems for larger supporting areas under for example the heel, becausethat peripheral area also extends across the foot close to the heelbone, where, consequently, a bead of liquid will press up against thetendons and muscles of the foot, which is very uncomfortable andpainful. The same effect will arise under the forefoot, where the liquidbead will settle itself especially in the transitional area between thesole of the foot and the toes. Therefore, commercially available insolesonly have cavities with very limited supporting areas.

[0008] There is a substantial demand for large pressure reducingsurfaces in footwear, especially within the orthopaedic field, forexample where an effective relief of the entire heel area is necessaryin the case of heel spur. Correspondingly, flatfootedness of theforefoot is best solved by a large pressure reducing surface.Furthermore, with shock absorption being a function of collision timeand collision area, a large surface will provide a better shockabsorption.

[0009] It is the purpose of the invention to provide an insole that isshock absorbing and at the same time pressure reducing, and where knowndisadvantages are avoided. In particular, it is the purpose of theinvention to provide a thin insole with improved high shock absorbingand pressure reducing properties.

[0010] This purpose is achieved with a shock absorbing and pressurereducing insole for footwear, of the type wherein said insole comprisesa top foil and a bottom foil joined along a closed path to provide atleast -one enclosed cavity, which is filled with at least one fluid,wherein in said enclosed cavity, additional joints are provided which ischaracterised in that said additional joint have varying heights forpromoting presence of liquid near the higher of said additional jointsas described in the characterising part of claim 1.

[0011] With an insole according to the invention, a support of the footis achieved through one or more enclosed cavities around those areaswhere a load is exerted by the foot, for example in the heel area or inthe area under the forefoot. To prevent that, due to continuous load bya part of the foot, for example the heel, there no longer is fluid, forexample gas, liquid or gel, under this particular part of the foot,these cavities are established in such a manner that they do not extendfrom the rear of footwear to the front of the footwear, thus preventingthe liquid from being displaced from the rear of the footwear to thefront of the footwear.

[0012] In the following, the invention will be explained with focus onthe areas around the heel and the forefoot, although it is within thescope of the invention that enclosed cavities can be established underother parts of the foot, if this should be appropriate.

[0013] The insole according to the invention is provided with additionaljoints in such an enclosed cavity. These joints are preferablyestablished along open paths. The term open path is used for paths thatare not closed, which means that the establishment of these joints doesnot result in new enclosed fluid containing cavities. The simplifiedterm open path implies not only elongated paths, but also point-likejoints. Through these additional joints, a number of advantages isachieved, which will be described in the following.

[0014] As experiments have shown for thin insoles that shall fit intoexisting footwear, it is of great advantage that the additional jointsare of varying height. In this situation, the fluid inside the insolecan be concentrated in particular places by locating higher additionaljoints in the vicinity of those places. For example, it is preferredthat the joints closest to the pressure area are the highest in order topromote the presence of liquid in the pressure area when no load by thefoot is put on this particular place.

[0015] Such a joint is easily obtained when welding is used for thejoining. Through welding, the foil material is melted and pushed towardsthe edge of the welding seam. By pushing the welding seam more closelytogether at one location that at another, for example by repeatedwelding at the same location, an edge on the welding seam is obtained atthat place which is higher than at the other.

[0016] Through load, the liquid is displaced from these areas andpressed into the areas surrounding the joints, where the cavity of theinsole is thin due to lower additional joints. Therefore, the liquidwill do work in order to push the top foil and the bottom foil apartclose to these lower joints. Thus, the liquid is prevented from flowingquickly, which increases the collision time as well as the collisionarea. Furthermore, the liquid will always adapt to the individual footshape and the load by the bone, regardless of the angle with which thefoot is placed on to the base surface and regardless of the design ofthe inner sole of the shoe, which in total provides an optimal shockabsorption.

[0017] While a shock absorption, as mentioned above, is achieved in thecase of a momentary load, a continuous load will have a pressurereducing effect, because the liquid will shape the insole to match thecontours of the foot, for example under the heel.

[0018] An insole according to the invention does not have the sameproblem as known insoles where the liquid in for example a round cavityunder the heel due to load is pushed from the middle of the cavity tothe periphery of the cavity with the effect that the heel no longer issupported by liquid. According to the invention, the additional jointscan be established in such a manner that they prevent the cavity frombecoming too thick at the periphery, thus, constantly maintaining partof the liquid inside the area where the foot causes the biggestpressure. Therefore, the desired pressure reducing effect is maintainedand at the same time the harmful transverse bead is avoided. As aresult, an insole according to the invention can be manufactured verythin and still maintain the desired shock absorbing and pressurereducing effect.

[0019] Furthermore, the additional joints have the effect that thestructure of the insole is more stable than that of other knownproducts, because the top foil and the bottom foil are joined in manyplaces and not just along the edge. This implies that the pressure ofthe liquid, when a load is placed on it, is distributed along a muchlonger welding seam, which may be the sum of a plurality of point-likewelding seams, so that the load per unit of length of the welding seamis strongly reduced, thus increasing the strength of the sole inaccordance with the number and length of additional joints. At the sametime, another great advantage is achieved, namely that creep does notoccur to the same degree as in soles according to prior art.

[0020] Advantageously the additional joints are established in an areaoutside a pressure area, where the pressure area is that area under theheel or forefoot, respectively, which is subject to the greatestpressure from the heel or forefoot, respectively. This ensures that theinsole is relatively high in the pressure area with a good absorbing andpressure reducing effect.

[0021] An insole according to the invention has proved suitable for thecontainment of liquid or gas under a higher pressure than atmosphericpressure. This has not been possible in the same way with known soles.In this connection, the additional joints, which prevent the surface ofthe insole from curving too much, are crucial. By using a higherpressure than in similar soles according to prior art the insole can bemanufactured very thin and still provide a very powerful shockabsorption and a heavily pressure reducing effect, which normally onlycan be achieved with much thicker constructions. Using thin insoles hasthe advantage that these fit into the existing footwear, thus, improvingthe already existing footwear of the user considerably. Furthermore,this causes the user to feel a high degree of stability from thefootwear, which is not always implicit if the insole is very thick,because the top foil of thick, liquid filled insoles tends to slidesideways with respect to the bottom foil and the outer sole of thefootwear.

[0022] Generally, it is a big problem to manufacture insoles where thefluid has a pressure that is above that of the atmosphere, because thejoining according to prior art has to take place in a pressurisedchamber. Alternatively, according to prior art, the joining takes placefirst after the cavities are filled with fluid under pressure, whichalso is a very difficult and expensive process. This is why insoles withfluid under excess pressure have not been commercially availablealthough they offer many advantages.

[0023] However, it has been proven that the production of additionaljoints in an insole according to the invention can be used as a verysimple and economic way of creating excess pressure of the fluid in aninsole according to the invention. As a first step, a top foil and abottom foil are joined along a closed joining path in order to create anenclosed cavity, where the cavity is filled with a certain amount offluid under atmospheric pressure. This first step is well-known. In thenext step, which is unique for the invention, additional joining pathsare established in the enclosed cavity, primarily through welding, alongopen paths in order to reduce the volume of the enclosed cavity. Hereby,a pressure which is above atmospheric pressure is obtained in thecavity. The more of the additional joints that are established, thesmaller is the volume of the enclosed cavity and the higher is thepressure in the cavity.

[0024] It is generally known that the majority of problems with painunder the heel or the forefoot are a result of the body weight beingconcentrated on very small areas on the sole of the foot, which causespainful concentrations of pressure. Today, these problems are soughtsolved orthopaedically by modelling a firm, thick insole which throughgeometrically elevated areas against the sole of the foot seeks to movesome of the mentioned concentration of pressure to other parts of thefoot. However, these insoles have many disadvantages of which can bementioned: They alter the positioning of the foot by forcing the foot toplace a bigger load on the outer edge of the foot, which with time oftencauses problems with knees, hips and the back; they prevent a naturalmovement of the foot, because the foot is forced into only onepositioning, which on the one hand often is uncomfortable and on theother hand reduces the blood circulation in the foot; they requirespace, which means that the user is forced to buying very expensiveshoes, combined with the fact that these shoes are far from fashionable,particularly in the opinion of women, which is a real problem to manywomen. In addition, those insoles themselves are very expensive.Regarding the economic aspect, it is important to be aware of the factthat, once the use of these firm insoles is commenced, the additionalexpenses to both shoes and insoles will be permanent for the rest of theuser's life.

[0025] Through the pressure reducing effect, an insole according to theinvention is highly pain reducing. Furthermore, the additional jointsare easily arrangeable in a manner to relieve the given pain areas inthe best possible way, which in most cases will have the effect that theinsole is of greater aid than the insoles known today. This is combinedwith the fact that the pressure reducing effect from the given pressurearea of the sole always follows the individual foot shape dynamicallyduring every thinkable foot movement, especially since the pressurereducing areas according to the invention can be established with alarge area. Furthermore, the insole does not alter the naturalpositioning of the foot, thereby preventing a harmfull load on knees,hips and back; the insole does not lock the foot movement, whereby theblood circulation in the foot is not reduced; the insole is thin,whereby the insole fits into the normal shoes of the user, even intoladies' shoes with high heels, which offers a very great advantage forthe user both in comfort and financially.

[0026] The insole has proven particularly advantageous for sports shoes.In the field of sports, maximal performance is generally desired. Inrelation to sports shoes, this translates into the demand for maximalshock absorption and best possible fit in relation to the inner sole ofthe shoe, such that the load receiving areas under the heel and forefootare as large as possible. As a rule, shock absorption is achievedthrough elastomers. Elastomers are, however, relatively heavy, which iswhy the construction of sports shoes always involves a compromisebetween the desired shock absorption and the weight of the shoe, as ashoe that is too heavy reduces the performance of the athlete. In manydisciplines, such as sprinting, basketball or tennis, specially mouldedinsoles are manufactured for the individual top athlete, where theinsole increases the loadable area as much as possible in order toincrease the collision area, thus, increasing the use of the shockabsorbing properties of the elastomers and reducing the weight of theshoes. Intrinsically, moulded insoles only have one form, which meansthat they never are able to follow all the movements of the foot Inparticular, it is difficult to shape the insoles optimally in relationto the angle with which the foot is placed onto the base surface, sincethis angle is dependent on both the speed of the athlete and thecondition of the base surface.

[0027] Through the containment of fluid and the physical laws for fluidmotion in the enclosed cavities, the insole according to the inventionwill always adapt to the individual dynamic foot shape of the athlete.This means that the insole always will provide the largest possiblecollision area regardless the foot shape of the athlete, the inner soleof the shoe, the angle with which the foot is placed onto the basesurface and the properties of the base surface. Additionally, the verysmall weight of the thin insole makes it particularly suited for sports.As a result, it is possible to make insoles for general sports shoeswhich correspond to and are much better than those insoles that areshaped individually for top athletes today. This is combined with thefact that it is possible to adapt the enclosed cavities and theadditional joints to top athletes, such that the insole offers thepossibility of shock absorption and dynamic relief at a previouslyunknown level.

[0028] The fluid for an insole according to the invention may comprisetwo or more liquids with different viscosity in order to optimise theshock damping properties. Also the fluid may contain small solid orelastic spheres, for example filled with gas in order to reduce theweight of the insole. Also particles may be suspended in the fluid inorder to adjust flowing and damping properties. For example, liquidswith colloidal particles are known to change viscosity in dependence ofmechanical action exerted on the liquid.

DESCRIPTION OF THE DRAWING

[0029] In the following the invention is described in more detail withreference to the drawing where

[0030]FIG. 1 shows an insole as seen from a direction normal to thesurface,

[0031]FIG. 2 shows a cross section of the insole along the line A-A,

[0032]FIG. 3 illustrates weldings of different height,

[0033]FIG. 4 illustrates a different embodiment of an enclosed cavity inthe heel area,

[0034]FIG. 5 shows the cross section C-C through the cavity at the heelarea,

[0035]FIG. 6 shows another embodiment with a large relief area at theheel,

[0036]FIG. 7 shows another embodiment where the additional joints areplaced in accordance with individual shock absorption.

[0037]FIG. 1 shows an insole 1 as seen from a direction normal to thesurface. The top foil and bottom foil are joined, for example by gluing,hot welding or ultrasound welding, along the edge 2 of the insole 1.Furthermore, an fluid filled cavity 6 is provided at the area under theheel through enclosure by a first closed path 3, 3′. A second fluidfilled cavity 7 is provided in the area under the forefoot throughenclosure by a second closed path 4, 4′, 4″, 4′″. In these two cavities6, 7, additional joints 5 have been provided along open paths.

[0038] As illustrated in FIG. 1, the additional joints 5 have beenprovided in an area outside a pressure area 8′, 8, which is indicatedwith a hatched curve. The pressure area is on the one hand that area 8under the heel, which is subjected to the highest pressure from theheel, and on the other hand that area 8′ under the forefoot, which issubject to the highest pressure from the forefoot.

[0039] Furthermore, the additional joints 5 may be arranged in a patternwhich impedes the free movement of the fluid in the cavity 6, 7. Whenthe cavity 6, 7 is subjected to a load which causes the fluid to bedisplaced from pressure area 8, 8″, the narrowed passages between theadditional joints 5 will damp the movement of the fluid, where themovement is indicated with curved arrows 24, 24′.

[0040]FIG. 2 shows a cross section through the insole 1 along the lineA-A as indicated in FIG. 1. If the insole 1 is not under the load of afoot, the insole 1 will be shaped as shown in FIG. 2a. At the outer edge11, 11′ of the insole 1, the top foil 9 and bottom foil 10 are joined.Furthermore, cavity 6, enclosed by the outer edge 11, 11′, hasadditional joints 5. In the middle of the cavity 6, the pressure area 8is situated. The outer areas 13, 13′, 14, 14′ are not as high as middlearea 12, because the additional joints 5 and the elasticity of the foils9, 10 prevent this. The shape of the outer areas 13, 13′, which areshown asymmetrically in FIG. 2a, are determined by the design of theadditional joints. Due to elastic forces, illustrated with arrows 15,between top foil 9 and bottom foil 10, the fluid is caused to flow tothe middle area 12, which is illustrated with arrows 16.

[0041]FIG. 2b illustrates the consequence of an external shock withpressure 17 on insole 1. The middle area 12 is then pressed together.The pressure will transmit to the remaining fluid, indicated with arrows19, causing the outer areas 13, 13′, 14, 14′ to expand, which isindicated with arrows 18. During this expansion, a mechanical work isperformed by pushing the of top foil 9 away from the bottom foil 10,which results in an absorption of the shock.

[0042]FIG. 2c illustrates how a very local load, as shown in FIG. 2b,causes a pressure reduction in a very large area 21 under the heel 20.

[0043]FIG. 3 illustrates weldings 22, 23 of different heights. In thefirst welding 22, the top foil 9 and the bottom foil 10 are joined witha relatively small change in the thickness of the foil at the positionof the welding seam, which is shown on FIG. 3a. Only very littlematerial has therefore been pushed to the edge 26 as indicated witharrows 25. Because of the small angle 28 between the top foil 9 and thebottom foil 10, the height 27 of the insole, therefore, will berelatively small at a distance from the edge, which is why this type ofwelding results in a low joint.

[0044]FIG. 3b shows a so-called deep welding 23. The foil thickness haschanged substantially and, therefore, much more material has been pushedto the edge 26′ as indicated with arrows 25′. Because of the steep angle28′ between the top foil 9 and the bottom foil 10, the height 27′ of theinsole will thus be relatively big at a distance from the edge 26′ ofjoint 23, which is why this type of welding results in a high joint.

[0045] By applying this technology, it is possible to design andmanufacture an insole according to the invention with a relatively largeamount of fluid in preferred areas. It is thus advantageous to vary theheight of the additional joints 5, preferably the height. 28, 28′ of thewelding 22, 23 such that the joints due to the weldings 23 closest tothe pressure area 8, 8′ are the highest in order to promote the presenceof fluid in pressure area 8′, 8 when this area is not loaded by thefoot.

[0046] The high-joint due to deep welding 23 and the low joints due tothe firs type of welding 22 are also indicated in FIG. 1 and FIG. 6 forillustration.

[0047]FIG. 4 illustrates another, embodiment of an enclosed cavity 6 inthe heel area. The additional joints 5 extend radially from pressurearea 8 and decrease in height with distance from the pressure area. Thisis illustrated in FIG. 4b, where the insole is shown in a cross sectionalong the line B-B with the perspective being towards the front of theinsole so that the additional joints 5′, 5″, 5′″ are visible as well. Inthis connection, it has to be pointed out that for purpose ofsimplification, the varying height of the additional joints is notillustrated in FIG. 4b. As the additional joints 5 decrease withdistance from the pressure area 8, the fluid will be concentrated in thepressure area 8.

[0048] The profile of the enclosed cavity in the cross section alongline C-C is illustrated in greater detail in FIG. 5. Because of theadditional joints 5 that extend radially, the profile is flat in thepressure area 8 when lacking the influence of external pressure andconcave in area 29 extending from pressure area 8 and to the edge 3. Theconcave shape, as opposed to a convex shape, ensures the largestpossible amount of fluid in pressure area S.

[0049] Furthermore, the concave shape causes a damping of the shock.This is illustrated in FIG. 5. When loaded 17, the fluid will be pressedaway from pressure area 8, as indicated with arrows 19, causing the topfoil 9 and the bottom foil 10 to be pushed apart. The force 30 directeddownwards from the bottom foil 10 will be transferred to the footwear,whilst the force 31 directed upwards in the top foil 9 will result in anelastic deformation of cavity 6. This deformation is achieved by themechanical work performed by the liquid on the insole, whereby themechanical energy caused by the shock is absorbed. As a consequence ofthe concave shape of area 29, which enables the largest possible amountof fluid to be available in pressure area 8 before the shock, arelatively large amount of fluid must be displaced almostinstantaneously from the pressure area This causes the shock absorptionand pressure reduction by an insole 1 according to the invention to befar better than by insoles known thus far.

[0050]FIG. 6 shows an alternative embodiment of an insole according tothe invention where the pressure area 8 is chosen to be relativelylarge.

[0051]FIGS. 7a and 7 b illustrate two cases, where the shock absorbingand pressure reducing area 8′, 8″ are individually shaped for twodifferent users. High joints 23 are indicated with thicker outlines. Aninsole according to the invention allows a very simplified optimisationof an individual insole. The insole may be manufactured withoutadditional low joints 22 and high joints 23 after which in accordancewith the need of the user, additional joints are welded into the insolein such a manner as to form the pressure area 8′, 8″ and to adjust theflow speed through the flow restricting joints 22, 23. Also by formingthe joints, the pressure inside the sole may be adjusted to be optimumfor the user, for example the sportsman.

[0052] On FIG. 7a and 7 b, the additional low joints 22, 22′ havedifferent sizes, which also is a factor in the optimisation process. Thetotal reservoir of fluid extends from the front welding 4′ to the rearwelding 4′″, which is located under the arch of the foot, where minimumpressure is applied. In practice, the insole may be truncated, forexample by cutting, along the rear welding 4′″ in order to obtain ashort insole only for the forefoot. This truncation may be performed bythe user after purchase of the insole in order to fit the insole intofootwear, for example a ladies' summershoe. In this case, the rear part32 may be without fluid inside. Likewise, only a rear part of the insolemay be used by the user for shock absorption from the heel. Such aninsole may for example be fastened to the user's shoe by glueing or withsticking tape.

[0053] An insole according to the invention is primarily produced with aheight of 2 mm, but the insole may have a different height, for examplebetween 0.5 mm and 10 mm.

[0054] Though the invention relates to an insole, it is within thecapability of the skilled man to use the aspects of the invention inconnection with ordinary soles, such as soles for sports shoes or otherfootwear, bicycle saddles, riding saddles, knee and shin protectors andon band aid against concentrated pressure on the side of the foot and ontoes.

1. A shock absorbing and pressure reducing insole for footwear, whereinsaid insole comprises a top foil and a bottom foil joined along a closedpath to provide at least one enclosed cavity, which is filled with atleast one fluid, wherein in said enclosed cavity, additional joints areprovided, characterised in that said additional joint have varyingheights for promoting presence of liquid near the higher of saidadditional joints.
 2. A shock absorbing and pressure reducing insoleaccording to claim 1, characterised in that said additional joints areprovided only outside a pressure area, wherein said pressure area isthat area under the heel that is subjected to the highest load by theheel and/or that area under the forefoot that is subjected to thehighest load by the forefoot.
 3. A shock absorbing and pressure reducinginsole according to claim 2, characterised in that said additionaljoints are closest to said pressure area are provided as the highest inorder to promote the amount of fluid in said pressure area.
 4. A shockabsorbing and pressure reducing insole according to any one of thepreceding claims, characterised in that said at least one enclosedcavity is delimited to support only a part of the foot and does notextend from the front of said footwear to the rear of said footwear. 5.A shock absorbing and pressure reducing insole according to any one ofthe preceding claims, characterised in that said least one enclosedcavity extends at least partly under the arch of the foot.
 6. A shockabsorbing and pressure reducing insole according to any one of the abovementioned claims, characterised in that the joints are weldings.
 7. Ashock absorbing and pressure reducing insole according to any one of theabove mentioned claims, characterised in that the pressure of said fluidin at least one additional cavity is above atmospheric pressure.
 8. Ashock absorbing and pressure reducing insole according to any one of theabove mentioned claims, characterised in that said at least one fluidcontains hollow spheres or particles suspended in said fluid.
 9. A shockabsorbing and pressure reducing insole according to any one of the abovementioned claims, characterised in that said at least one fluid-comprises two liquids having different viscosity.
 10. Method forproduction of a shock absorbing and pressure reducing insole forfootwear according to any preceding claim, wherein a top foil and abottom foil are joined along a closed path to provide an enclosed cavityin which fluid is provided under atmospheric pressure characterised inthat additional joints are provided with varying heights in saidenclosed cavity to reduce the volume of said enclosed cavity in order toprovide a pressure in said enclosed cavity which is above atmosphericpressure.
 11. Use of a shock absorbing and pressure reducing insoleaccording to claim 1-9 for sports shoes.